Pls help tell the right answer

The square root of 9x plus 7 plus the square rot of 2x equall to 7

Which graph represents the equation y =4x

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex